Process for recovering solvent from smokeless powder.



F. l. DU PONT.

PROCESS FOR REOOVERING soLvENT FROM sMoKELEss POWDER.

' l APPLICATlON FILED IANA, |917. m. Patented P61111, 1919.

Inventur.'

U20/SI5@ 1 n@ Attorney..

leo

.the heater and normen rnancis r. nu roter; or winniiiieron DELAWARE, ASSIGNGR TO DELAWARE GHEMCAL ENGINEERING COMPANY, 0F WILIVINGTON,DELAWALBE, A COB,-

PRATION OF DELAWARE.

PECESS OB. BIECOVEBNG SOLVENT FROM SMGKELESS POWDER.

idi,

` Application led Jennery To aZZ whom 'it may concern:

Be it known that l, a citizen of the United States, residing at Wilmington, county oi- N ew Castle and State of Delaware', have invented a new and useful improvement in ?rocess for Recovering Solvent; from Smokeless Powder, of `which the ollowinc' is a full, clear,and ex act description, reiperence being had to the accompanying drawings, which'iorm a part of this specication. I i

ln the recovery of solvent, such as ether and alcohol, from materials siich as` smokeiess powder, it is customary to circulate air, by means of a iii-echanicai blower or by difterence of temperature,successively through the recovery chambers, a condenser| cooled with a' coil'containing circulating cold water or refrigerated brine, a heating chamber heatedby a steam or hot water coil, and thence bach tofand through the recovery chamber.

theoutside ci' the in the .con-

coii oi pipe denser and drips ont from an outlet as tast.

as it collects. v y n This system 1s open to a number oi cincotions, some oi them quite serions. During the operation there cannot exist inthe sys-v teni an atmosphere oi pure vapor, as th 'condensing coil will, hy the shrinkage ner to the vapor being condensed out oi the air,

always sack in a little air through the re covered solvent enit or through any other leak vthat may exist in the apparatus, this air being circulated iaround continnonsiy with the vapor; The only condition -ander which this would-not happen would he an insnihciency of the condenser, in vwhich case some of the vapor would escape at the solvent ont let and he lost. Again, in the usual system, the condenser are in the same stem and are constanti. Aenriching against goh other. 'Hence' there isl diculty in maintaining the powder mass .at the desired temperature; and any attempt to unduly 111-' crease the circulation will merely transfer heat` from the heater tol the condenser .in a necessarily wasteful manner. Again, mas-i much as the condenser must operate upon a certain volume oi air 'as well as apeny the vapor, a relatively low'teinperature must he maintained in the condenser, ice

cooling heing necessary.

. Specicaticn of Letters Patent.

Francis' l. DU ?oN'r,

vThe recovered solvent collect-son a, 1917. Serial No. 1:10536.

The objects of my invention are: to eziclude air from the circulating system so as to maintain therein an atmosphere of pure vapor; to maintain the powder mass wit certainty at the desired temperature; to dispense with the necessity for ice cooling i to avoid the bucking against each other of the condenser and the heat and waste ofk cooling power, thereby. edecting a more economical carrying ont of the operation; ,to expedite the process; and to avoid conditions rendering possible imperfect condensation of the solvent. y

A convenient new process is illustrated in the accompanying drawing, which shows, also, a preferred invention.

embodiment of my apparatus in sectional elevation.

' raten-ten rea. ii, raie.

heater; to avoid waste oi means for/carrying out my I The' recovery chamber a, containing av p layer of smokeless powder or similar material m, is provided with a cover l), which is Imaintainsd closed during the operation. "heating chamber c contains a coil Z through which is circulated hot water or steam. pipe e connects the heating chamber c with the upper part oi' the recovery chamber a andpipes f and g connect the heating chamber c with the bottom of the recovery chamher c, a-Eording an endless path for the cir culation oi'air and vapor, this circulation heing induced in the direction of the arrows by means oi a fan or blower 7b interposed in the pipe j.

An'overflow passage z' connects with pipes ,f `and q at their junction and communicates with a condenser',- the latter comprising a vessel y' containing water in whic is 1mmersedl a 'coil of pipes is communicating with the passage a' having at its lower end an outlet m 'for the escapeoi air or condensed` vapor, as hereinafter overl-low pipe fn, is provided for the water.

lt is necessary to keep the water in the condenser only at a temperature below the boiling point of the liqui recovered.v

The chamber c should-.he point requiredio maintain the circulating vapor above the ceiling point oi the liquid which is to he resevered.

l 'in the case oi a mixed solvent', like described. An

a which is tang` wil@ heated -to the Mill perature of the circulating vapor distinctly above the boiling point of the ether but below the boiling point, ol the alcohol.

The' operation is as follows Upon starting, the airin the endless oirculating system is first heated. Owing to the fact that the condenser is not in the endless circulating system, the material in chamber c soon becomes heated throughout its mass. As soon as sutiicient vapor is evolved from the mass, all the airis expelled by the vapor which is continually being driven oil from the mass by the heat. This air is expelled through the overiiow pipe i and coil c and escapes at the recovered solvent exit m. lAfter the expulsion of the air, which takes place almost immediately after starting, there is established a circulatipn of ure vapor free from air, which, havlng a higher specific heat than air, is more eilicient. The ,vapor constantly being displaced by the vapor continually being driven of passes continuously into the condenser.

The advantages of the above describedsystem may 'be stated as follows:

Inasmuch as the condenser is excluded from the endless circulating system, the cold coil is not bucking 'against the hot coil, and

there is therefore no diflicul'ty in maintainingthe powder mass at an desired temperature, as a large amount o air or vapor may be circulated through thel system without any waste of heat or cooling power. lln no event can there be any transfer of heat from the heater to the condenser in a wasteful manner.

Since,Y after the displacement of the air at the start ot' the operation, no other air can pass-or leak into the system, the condenser operates only upon pure vapor and condensation takes place as soon as a-temperature is reached below the boiling point of the liquid which is being condensed; ice cooling,

therefore, being unnecessary.

.By rca son of the foregoing conditions, waste of heat or of cooling power is avoided, the operation is carried on expeditiously and economically, and no conditions are p1 .sent rendering possible imperfect.condensation of the solvent.

Having now fully described my invention, what I desireto claim and protect by Letters Patent is:

l. lThe process of recovering solvent, such as alcohol and ether, from smokeness powder and similar material, which consists in gradtally vaporizing the solvent contained in the material, segregating a part of the vaporized solvent and subjecting only the part segregated 'to the action of a cooling' medium to eect its condensation, and returning to the rebecca materiel ,the uncooled remainder for the vaporized solvent.

2. The process of recovering solvent, such as alcohol and ether, from smokeless powder andpsimilar material, which consists in establishing an endless circulation of fluid through said material and simultaneously heating said fluid, thereby gradually Vaporizing the solvent contained in the material, affording an outlet for the excess heated vapor thus constantlyl being formed and subjecting only said escaped excess vapor to the influence of a cooling medium.

3. The process of recovering solvent, such as alcohol ,and ether, from smokeless powder and similar material, which consists in es.- tablishing an endless circulation of fluidl through said material and simultaneously n as lalcohol and ether, from smokeless powder.

and similar material, which consists in establishing through the powder an endless flow ot' the vaporized solvent that has 'been driven off from the powder and continuously applying heat to the flowing vapor, thereby continuously driving' from the powder additionalvapor, affording an outlet from the endless vapor path for the excess of vapor thuscontinuously forming, and cooling only said excess vapor thus escaping from said' endless vapor path, whereby the vapor constantly passing intothe powder is vapor that has not been previously cooled.

5. The process of recovering solvents, such as alcohol and ether, from smokeless powder y and similar material, which consists in maintaining, by circul-a-tlon through a mass of the powder, an atmosphere consisting entirelyA of the vapors of said solvent, supplying by means of a heater interposed in the circulating circuit the heat units which have been abstracted by the conversion of the solvent from the liquid to the gaseous state, conducting the excess of vapor continually formed `by the addition of aforesaid heat units away from the circulating system, andfcondensing the vapors thus conducted from the circulating system.

In testimony of which invention, I have4 hereunto set my hand, at Wilmington, Delaware, on this 3rd day of January, 1917.

FRANCIS l. DU PONT. 

